If she's not going to play in sessions, where the tunes are pretty much in the key of D, then she might like a flute in G, which is smaller and easier on the hands. (Its lowest note is a G.) I have one made by Ralph Sweet and another which is simply called a Renaissance flute. (Renaissance is the brand name.) The fingering of a G flute is similar to the fingering of a recorder in F.

My G flutes are 18 inches long, and the distance from the top hole to the bottom is 6.5 inches.

The D flute is 24 inches long, and the distance from the top hole to the bottom is 8.5 inches. As I said, I needed to add a key to be able to play it. I got it from the House of Musical Traditions in Takoma Park, Maryland. They mailed it out and gave me some time to try it out and send it back if need be.